过去进行时 — 英语选择题
题目
昨晚9:10，图书馆管理员发现一把伞落在阅览室。监控显示，9:00到9:20，Leo一直在阅览室整理书架；Mia在9:05到9:15擦窗户，9:15到9:25整理书架。根据监控，9:12时谁正在擦窗户？A. Leo was wiping the windows. B. Mia was wiping the windows. C. Leo was arranging the bookshelves. D. Mia was arranging the bookshelves.